• 한국정보통신학회논문지
• /
• 제18권9호
• /
• pp.2131-2139
• /
• 2014

본 논문은 무선통신 환경에서 이진 부호화된 네트워크 코딩 기술을 고차원 변조 방식과 결합하는 방식을 다룬다. 기존의 물리계층 네트워크 코딩 기술에서 중계 노드는 2개의 소스 노드에서 수신된 심볼들 사이의 엄격한 전력 제어와 위상 보상을 요구한다. 그러나 무선 페이딩 채널을 고려하면 소스 노드들에서 채널을 미리 알고 보상하는 것은 쉽지 않다. 따라서 본 논문에서는 중계노드에서 수신단 채널 정보만을 이용하는 네트워크 코딩 수신 기법을 고려한다. 특히, 각 소스 노드들이 QPSK, 16QAM 등과 같은 고차원 변조방식을 사용했을 경우 사용할 수 있는 수신 기법을 제안하고, 채널 부호화 기법이 적용되었을 경우와 적용되지 않았을 경우에 대하여 그 성능을 분석한다.

• 전자공학회논문지CI
• /
• 제42권4호
• /
• pp.25-32
• /
• 2005

모바일 디바이스, PDA 센서들의 확산은 실생활 공간이 지능적이고 향상된 서비스를 제공하는 스마트 공간으로 전환되는 유비쿼터스 컴퓨팅 환경이 구축될 수 있도록 하였다. 그러나 보안문제 특히 적절한 인증 및 접근 제어 기술의 부재로 말미암아, 실생활에서의 이러한 컴퓨팅 패러다임의 변화에 있어, 방해 요소가 되고 있으며, 또한 유비쿼터스 컴퓨팅 환경에서는 보안 대책을 마련하고, 사용자의 프라이버시 보장 또한 매우 중요하다 본 논문에서는 유비쿼터스 컴퓨팅 환경을 위한 사용자 프라이버시를 위한 익명성이 보장되는 효율적인 사용자 인증 및 접근 제어 모델을 제안한다. 본 논문의 제안 모델은 공개키 암호 기술이 아닌 MAC 기반의 익명 인증서와 보안 연계 토큰을 이용하여, 사용자 인증 및 접근 제어를 수행함으로써, 컴퓨팅 연산 능력이 컴퓨팅 연산 능력이 비교적 떨어지는 디바이스들에 적합한 모델이다. 또한 암호 연산 처리 측면에서, Kerberos 시스템과 비교하였을 때, 전반적으로 우수함을 알 수 있었다.

• Journal of Computational Design and Engineering
• /
• 제3권3호
• /
• pp.250-265
• /
• 2016

Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only "as-planned" situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM) with "as-is" environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap) data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

• 한국실내디자인학회논문집
• /
• 제20권1호
• /
• pp.117-127
• /
• 2011

Townhouse have been developed as alternative housing types for combining the characteristics of detached houses and high-rise apartments, Much research on townhouse have investigated physical environments of townhouse and provide a number of planning factors to be considered. However, these factors do not reflect the residents' experiences of the environments sufficiently. The aim of this research is to investigate residents' satisfactions in townhouse as an exploratory study which can be a basis for the improvement of residential environments in townhouse. First of all, we selected a target townhouse and conducted a field study to examine the existing state of the townhouse. Then a customized questionnaire was developed and distributed to residents in the townhouse for investigating their satisfactions on the residential environment. The questions included are divided into four categories; site environment, unit space, community area and housing management. Through the statistic analyses of the residents' responses, the residents' satisfactions of the residential environment were identified. Especially the residents' satisfaction on the community area, which revitalizes neighborhood relationships, is very high. They were also satisfied with the conditions of the sub-categories, 'a distinctive exterior' 'a private planning', 'outdoors' and 'landscapes', in townhouse. In conclusion, we suggested considerations for the improvement of the residential environments and the quality of life in townhouse.

• 천문학회보
• /
• 제44권1호
• /
• pp.40.3-40.3
• /
• 2019

There is growing evidence for the dependence of Type Ia supernova (SN Ia) luminosities on the environments. The origin of this correlation, however, is under debate. In order to explore the physical origin of the trend in detail, we analyze SN Ia light-curves by combining a sample of 1231 SNe Ia over a wide redshift range (0.01 < z < 1.37) in various SN surveys and employing two independent light-curve fitters of SALT2 and MLCS2k2. Although SALT2 is the most widely used fitter in the SN community, MLCS2k2 has a novelty in the context of an investigation of the luminosity evolution of SNe Ia. For this reason we use both fitters and analyze them separately. We also determine a stellar mass and a star formation rate (SFR) for a sample of ~600 host galaxies. In addition, because recent low-redshift studies suggest that this dependence manifests itself most strongly when using the local SFR at the SN location, we introduce a new method to infer the local environments by restricting the SN Ia sample in globally star-forming host galaxies to a low-mass host galaxy subset (${\leq}10^{10}M_{\odot}$). We find that SNe Ia in low-mass and star-forming host galaxies are fainter than those in high-mass and passive hosts, after light-curve corrections. Especially, for the first time in host studies, we show that SNe Ia in locally star-forming environments are $0.081{\pm}0.018$ mag fainter ($4.5{\sigma}$) than those in locally passive environments from the sample including SNe at the high-redshift range. Considering the significant difference in the mean stellar population age between these environments, the result would suggest that the origin of the environmental dependence is the luminosity evolution of SNe Ia.

• 대한물리치료과학회지
• /
• 제16권1호
• /
• pp.31-39
• /
• 2009

Background: Community ambulation has been recently recognized as one of the most essential factors of activities of daily living in patients with post-stroke hemiparesis. This study aimed to compare walking velocity and step number in 5 community situations in patients with post-stroke hemiparesis. Methods: Ten chronic stroke patients volunteered for this study. The main variables analyzed were walking speed and step number, and these were measured in 5 different community situations: a physical therapy room, a parking lot, a bank, a crosswalk, and a hospital lobby. The measurements obtained for walking in the physical therapy room were measured using a 10m walk test and were used as baseline data for comparison with each option. The ambulation distance was set at 300m for the parking lot and the bank and 150m for the crosswalk and hospital lobby. For data analysis, walking speed and step number were standardized with the distance options of each ambulation. Results: Compared to the walking speed in the physical therapy room, those in the other situations, except for the parking lot, were significantly different (p<.05). Moreover, there were significant differences in the speeds between the bank and the parking lot and between the parking lot and the crosswalk (p<.05). Compared to the step number in the physical therapy room, those in all situations except for the crosswalk were significantly different (p<.05). Further, there was a significant difference in the step number between the bank and the crosswalk (p<.05). Conclusion: The walking ability of patients with hemiparesis in real environments within a community could be different from that in a physical therapy room. Therefore, the evaluation of walking should be performed in a variety of community situations.

• International journal of advanced smart convergence
• /
• 제4권1호
• /
• pp.18-30
• /
• 2015

As the speed of networks that subscribers can use has greatly increased, demand for high-quality broadcast content, such as from Internet Protocol Television (IPTV) and Video on Demand (VoD), is likewise increasing. Therefore, while broadcasters are increasing content and channels, they are striving to improve consumer quality of experience (QoE) to differentiate themselves from competitors, including by producing higher physical-quality content. Recently, subjective measurement methods have been internationally standardized as the most reliable approach for measuring and evaluating IPTV QoE. However, a majority of these methods are performed in experimental environments and are based on the extremely brief viewing period of approximately ten seconds using original reference videos. It is actually difficult to apply standard evaluation methods based on a ten-second viewing interval to assess real broadcast watching of IPTV or other services that involve a longer time (i.e., more than thirty minutes). In this paper, we therefore propose a method that accommodates actual viewing environments. Using the mean opinion score, we experimentally analyze the effects of evaluation interval changes under actual conditions in which IPTV service is provided. In addition, we propose improvements by applying the results into actual live broadcast IPTV service and by analyzing consumer service QoE.

• 한국실내디자인학회논문집
• /
• 제27권2호
• /
• pp.166-174
• /
• 2018

This study examined the indoor exercise environment use and needs of older adults. The target population was seniors aged 60 years and older living in a newly developed apartment complex. Variables include demographic and housing characteristics, status of exercise, and indoor exercise environmental evaluation and needs. A total of 102 data items were analyzed using frequency, t-test and ANOVA. Noteworthy results are as below. First, community centers and community welfare centers were the most desirable exercise environments because of affordability, exercise programs/spaces. Such exercise environments should be developed in more locations for increasing numbers of seniors. Second, indoor exercise environments need to be improved based on seniors' physical capabilities and environmental behavior. Third, supportive spaces such as restrooms, shower rooms, locker rooms should be carefully designed. Fourth, seniors wanted to have walking trails and indoor swimming pools, the most desirable exercise spaces, within ten to 15 minutes walking distance.

• 한국학교ㆍ지역보건교육학회지
• /
• 제17권1호
• /
• pp.59-73
• /
• 2016

Objectives: The working environment affects employees' physical and mental aspects, and has a deep associations with depression. The purposes of this study are to investigate how hazardous environment working experience impacts on depression, to provide rationale and practical implications for reducing depression and drinking. Methods: This study targeted 215 dental hygiene students from 3 universities located in Gyeonggi-do from November 30 to December 4, 2015. We analyzed the data with frequency analysis, descriptive statistics, t-test. One-way ANOVA, Pearson correlation coefficient, Regression analysis by using SPSS. Results: This study showed that experience working in hazardous environments increased depression and alcohol drinking, on the other hand alcohol drinking reduced depression. In addition, experience working in hazardous environments effected on depression indirectly through mediating of drinking, subjective health had not role of Moderating Effects between experience working in hazardous environments and depression. Conclusions: In order to reduce workers' depression and alcohol, the improvements of harmful environment are needed. For this governments and local governments should efforts to support enhancing workplace environment, to develop model of standard work environment, and to change employers' awareness on the harmful environment.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
• /
• 제17권2호
• /
• pp.45-52
• /
• 2011

The visual sensory information in physical environments can induce or reduce occupants' stress. In healthcare settings, positive environmental stimulations can promote patient well-being by reducing their stress: poor health environments work against a patient's health. Changing the color in a patient room is an inexpensive process and thus finding better colors for healthcare settings is a cost effective method of improving healing environments. Color may have important implications for pediatric patients, but the investigation of Korean populations has been non-existent. The purpose of this study was to investigate Korean pediatric patients' color preferences for patient room design. The color preferences from 50 Korean pediatric patients were recorded and investigated for gender effects. A simulation method was used because of its reliability and feasibility, allowing for investigating the value of color in real contexts and controlling confounding variables. The overall color preferences from Korean pediatric patients showed that they preferred blue the most and white the least. Gender differences were found in red and purple. Girls preferred red and purple more than boys. The results from this study can help healthcare providers and designers better understand appropriate colors for Korean pediatric patient populations.